This invention relates to weighing devices for weighing heavy loads, and particularly to a weighing device incorporated in railroad cars and which indicates weight of the car and load.
While this invention has many uses in the railroad industries wherein it is desirable to know the weight of a railroad car and a load carried therein, one contemplated use is in the steel industry wherein scrap steel is loaded onto railroad cars and thus transported to a furnace where the steel is melted in large ladles. In some instances, the molten steel is then transferred to railroad cars lined with firebrick so as to prevent rapid cooling of the steel and the loaded car transported to a casting shop or other facility where the molten steel is poured or otherwise worked. In this instance, occasionally the mill or other facility experiences delays from breakdowns or other bottlenecks that prevent the molten steel from being immediately used, which results in the cars filled with molten steel sitting in a railyard sometimes for several days. While the firebrick lining of these cars will prevent rapid heat loss of the molten steel during this time, if the steel becomes too cool it will harden in the car. If this happens, the car and hardened steel therein must be scrapped as there is no practical way to retrieve the steel from the car. This in turn presents a disposal problem. Thus, it would be advantageous to know, in addition to weight of the car and molten steel, location of a particular car and temperature of the molten steel carried thereby.
In other instances, weight of particular types of scrap steel to be melted and which is being loaded onto a railroad car must be known in order that the salvaged steel be of a quality commensurate with its intended use. For instance, if steel is contaminated with too much copper, it cannot be welded. In other instances, proportions of chrome, molybdenum, vanadium and other materials used in alloys of steel must be maintained or adjusted in accordance with a desired product. Where scrap steel is organized in accordance with its type, a particular load of scrap loaded into a railroad car might contain 10,000 pounds of one type scrap steel, 15,000 pounds of a second type of scrap, 20,000 pounds of a third type of scrap, and so forth until the railroad car is loaded with approximately 200,000 to 500.000 pounds of scrap.
To date, the relative quantities of each type of scrap was estimated, resulting in a relatively high rejection rate of the melted steel. Using Applicant""s weighing system, this rejection rate has declined by approximately 50% or more.
In addition to the necessity of weighing large amounts of metal, a system for measuring scrap must be extremely durable, as conditions in a scrap yard are harsh. With respect to a railroad car on which scrap is loaded, such loading is done by a crane or large mobile loader similar to a front-end loader or a grapple, with the scrap being sometimes dropped onto the bed of the railroad car. Thus, this application demands extreme durability and ruggedness of design in order to withstand daily pounding of large quantities of scrap steel falling into the railroad cars as described. Further, operation of the weighing device must be jam-free, as any type of jamming of the weighing device would render it inoperable. Here, prior art weighing devices have proved unreliable because they have used platforms in or on the railroad car. Scrap was loaded on these platforms to be weighed, but pieces of scrap and other debris would become lodged under the platform or between the platform and sides of the railroad car. When this happens, the prior art scales become inoperable or unreliable.
In accordance with the foregoing, it is one object of the invention to provide a weighing system for weighing large quantities of scrap metal prior to melting in a foundry or mill. It is another object of the invention to provide a weighing system for weighing an insulated railroad car containing molten metal. It is another object of the invention to provide a weighing system for railroad cars that includes a radio transmitter for transmitting a radio signal to a receiver, the radio signal including indications of weight of the railroad car and a load therein. Two or more receivers may be used to determine location of the railroad car, or the radio signal may contain location information indicative of location of the car. It is yet another object of the invention to provide a weighing system that is easily retrofitted to existing railroad cars, and which is rugged and durable. Other objects of the invention will become apparent upon a reading of the following specification.
A weighing system for weighing very heavy loads, on the order of 500,000 lbs. or so, is disclosed. In one application for weighing railroad cars, a ring is positioned or mounted to a disk on the underside of the railroad car that interfaces with a well in the wheel truck assembly, with a lower region of the ring extending below a lower surface of the disk. A load cell is mounted or otherwise configured in the lower region of the ring, and in turn extends below a lower edge of the ring. Typically, the disk on the railroad car would fit in the well of the wheel truck assembly, but in this embodiment, the disk of the load cell extending below the ring fits in the well of the wheel truck assembly. The upper surface of the load cell bears against a lower surface of the disk, and the lower surface of the load cell bears against the bottom of the well. Relative displacement between the upper surface and the lower surface of the load cell as a load is applied causes an electrical signal that varies directly with the load to be developed.